This invention relates to a reel leaf spring attached to the underside of a video tape cassette for supporting the hubs of tape reels rotatably mounted on the tape cassette base, and related methods of assembly.
A conventional video tape cassette includes a base and a cover, each made of plastic. The assembled base and cover, accommodate a pair of tape reels, each including a hub for winding magnetic recording tape therearound.
The cassette also usually includes a "coined" reel leaf spring, i.e., a spring stamped from a flat piece of stainless steel, such that arms are formed to extend from both sides of a central, flat portion, as described in U.S. Pat. Nos. 4,368,860 and 4,662,579. The reel leaf spring is fixed at a central flat portion on the underside of the tape cassette cover. That is, holes formed centrally in the spring receive corresponding plastic projections formed at the central flat portion of the cover. The projections are then welded to extend around the holes and hold the leaf spring relative to the cover.
With the arrangement described above, when the cover including the reel leaf spring is assembled with the tape cassette base, both of the free ends of the arms of the spring contact the hubs of the respective tape reels and bias the tape reels downwardly, so that the tape reels are rotatably retained in position.
Assembly of this design is relatively labor intensive. That is, holes must be accurately formed in the leaf spring, corresponding projections must be molded on the cassette cover, and the spring must be mounted so that the holes properly receive the projections. After positioning of the spring on the cover, but before welding, it is possible that the spring could be dislocated relative to the projections while progressing in the assembly line. The projections must then be welded to hold the spring. Of course, a relatively expensive welder is required which must be adjusted for different plastic materials. All of these steps, of course, raise the cost of the entire cassette.
Further, with cassettes, as with all plastic consumer goods, a need exists to find ways to re-cycle the products instead of merely depositing them in land fills. Someday perhaps, it may be necessary to return pre-recorded video cassettes to be reloaded with new tape, but re-using the rest of the cassette, much as glass or plastic beverage bottles are currently returned and refilled.
Finally, if a defect is found in either the leaf spring or cover of the conventional cassette, the leaf spring can not be removed without damaging both the spring and cover. These parts could not be re-used, but would have to be scrapped, which also increases overall production costs and energy costs.
The prior art discussed above still does not include the most cost-efficient reel leaf spring and cassette cover combination, one which lends itself to easy disassembly and re-use, or related methods of assembly having the fewest steps.